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291.
In this study we determined the levels of trace elements (zinc, copper, lead, cadmium and mercury) in three layers of bones
of the hip joint (cartilage, compact bone and spongy bone) of 30 red foxes (Vulpes vulpes) from north-western Poland. Concentrations of Cu, Zn, Pb and Cd were determined by atomic absorption spectrophotometry (ICP-AES)
in inductively coupled argon plasma using a Perkin-Elmer Optima 2000 DV. Determination of Hg concentration was performed by
atomic absorption spectroscopy. In cartilage, compact bone and spongy bone samples from the red fox, median concentrations
of the metals studied could be arranged in the following descending series: Zn > Cu > Pb > Cd > Hg, the values ranging from
142 to 0.002 mg/kg dw. There was a significant difference in Cu concentrations, among all the materials analyzed, with much
more Cu found in spongy bone than in compact bone. Significant differences were also noted in the case of Hg concentrations
in cartilage with compact bone and the spongy bone, and between concentrations of this metal in compact bone and spongy bone.
In males, the concentration of Hg in spongy bone was greater than in females. Younger foxes had a higher concentration of
this metal in cartilage than adults. The strongest synergistic relationships were observed in spongy bone between the Zn and
Cu, Zn and Cd, as well as between Cu and Cd. Statistically significant antagonistic relationships were detected between zinc
and lead in compact bone. In addition to monitoring studies conducted on the abiotic environment, an urgent need exists for
long-term monitoring of concentrations of heavy metals with long-term effects on living organisms. An important addition is
provided by biomonitoring studies on domesticated and free-living mammals, including Canidae. 相似文献
292.
293.
Juan F. Marquez Ruiz Kinga Kedziora Mary O’Reilly Jacqueline Maguire Brian Keogh Henry Windle Dermot P. Kelleher John F. Gilmer 《Bioorganic & medicinal chemistry letters》2012,22(24):7573-7577
Budesodine is a synthetic glurocorticoid that undergoes substantial first pass metabolism, limiting systemic exposure. Its use in treatment of inflammatory bowel disease would benefit from a targeting strategy that could lead to a local topical effect, improving safety and increasing anti-inflammatory efficacy. A two-step prodrug strategy involving azoreduction/cyclization that we developed previously for prednisolone is here applied with some variations to budesonide. The budesodine prodrugs were tested using an in vitro azoreductase assay simulating human colonic microflora. The kinetics of amino steroid ester cyclization and its pH dependence was also evaluated. The stability of the prodrugs systems in simulated human duodenal and gastric fluid was evaluated to determine the likelihood of intact intestinal transit. The propionic acid derived prodrug 3 undergoes rapid activation by Clostridium perfingens and its putative reduction product cyclizes with acceptable rapidity when synthesized independently. These properties of 3 suggest that it has potential in management of ulcerative colitis. 相似文献